The present invention is generally directed to tubular handrail structures and, more particularly, to a quick-connect connector for the interconnection of tubular handrail members.
Tubular handrails are commonly used in shopping malls, office buildings, factories, parking lots, stadiums, balconies, and in many other places where it is desirable to offer a supporting structure for pedestrians in case it should it be needed or to protect people from potentially hazardous conditions. Tubular handrail structures typically comprise prefabricated rail members horizontally disposed, or at least located parallel to the path of travel of the user, and corner, support post, and other members designed to interconnect with and support the rail members. The rail members are typically hollow tubes of a corrosion resistant material and must be supported at each end. The hollow feature results in reduced weight and the length of the rails is limited to avoid bowing. At each of their ends, the rail members are connected to a vertical post typically anchored to a solid base, such as the ground.
These prefabricated members are typically joined together to form the handrail at an installation site through the use of welding, adhesive bonding, or mechanical fasteners, such as threaded parts. While welding, adhesive bonding, and mechanical fasteners generally provide strong and reliable connections, each method has certain drawbacks. Welding, for example, is time consuming and expensive and requires skilled workmen and special equipment. Further, a weld is a permanent connection and a weld-connected structure is generally a permanent structure and is confined to use where it was constructed, unless it is small enough to be portable.
The traditional threaded technique used in the past for many handrails also has disadvantages. For example, in one such threaded approach the rails comprise pipe that is threaded at each end and the vertical posts include female threaded connectors. The rails are screwed into the female connectors during assembly and then the vertical posts are securely mounted to the ground surface. Threaded pipe is expensive and time consuming from both the standpoint of the expense needed to provide the threads on the pipe, as well as the time needed to thread the pipe into the fitting to establish a connection. Such construction requires the use of wrenches for turning the rails into the threads of the post, and the rail must be screwed into posts at both ends at the same time, making the process somewhat difficult.
A wide variety of mechanical fastening devices have been developed to interconnect handrail members in addition to the typical threaded approaches. Although many of these mechanical devices are quite effective in that they firmly clamp or otherwise connect the various parts together and are durable, they are also cumbersome. Some involve the transport of many additional parts to the installation site. Others involve bolt heads and/or clamp plates that protrude from the handrails creating a possible safety concern and an unsightly visual appearance. Protruding bolt or screw heads can cause injury if not rounded or made blunt. Rounded or blunt heads can make it difficult to obtain enough torque for assembly. Even the traditional pipe thread approach does not result in a smooth appearance although it does result in a robust railing structure.
One such device is shown and described in U.S. Pat. No. 5,615,968 entitled xe2x80x9cHand Rail Coupler System,xe2x80x9d issued to Verenski et al., Apr. 1, 1997. Verenski describes joining a pair of handrail sections by fitting a center member inside the two sections to be joined and fitting a pair of clamp-plates about the exterior of the sections. A through-bolt is used to generate compressive force between the clamp-plates and the sections to be connected, with the center member providing internal reinforcement. However, the cap end of the bolt remains outside the tubes and is exposed to the user, creating a possible hazard and lacking a streamlined appearance.
Wedge blocks with draw-bolts are also commonly used to interconnect corner or branch handrail members with straight handrail members. An example of this approach is described in U.S. Pat. No. 5,556,218, entitled xe2x80x9cTubing Connector,xe2x80x9d issued to Horner, Sep. 17, 1996. In Horner, a corner member is formed with a wedge end-fitting and a separate wedge block. The wedge block is threaded to accept a draw-bolt while the wedge includes a clearance hole for the draw-bolt. The draw-bolt is inserted from the corner member through the wedge and is threaded into the wedge block. The wedge and wedge block assembly are then slid into a straight member. As the draw-bolt is tightened, the wedge forces the wedge block to expand against the walls of the straight member creating a tight friction fit which holds the wedge block within the straight member, thereby forming a joint between the corner member and the straight member. While it would appear that this mechanism is capable of firmly clamping the parts together, it is relatively complex and requires a relatively large number of parts. Bolt ends must be accessible for controlling the clamping action.
In many cases, it is desirable to have a decorative railing with smooth, continuous joints where the exterior surfaces of the pipe and fitting meet. Inexpensive, reliable, and aesthetically pleasing fittings of a slip-on type for connecting lengths of structural pipe to each other and to structural members are desirable. However, many prior art devices use expansion fittings such as internal expanding parts, or other complicated mechanisms. Such approaches degrade the reliability of the structure due to the relatively large number of parts, each of which may fail or be improperly installed. Smooth, aesthetically pleasing handrails have the added advantage of not having protrusions that can cause cuts or bruises to hands that may be slid along the rails. Previously, handrails with a seamless or near-seamless appearance have only been obtainable through the use of welded or bonded connections, that require skilled assembly, as discussed above, or with relatively complex mechanical devices requiring an undesirable large number of parts and assembly labor.
It would be desirable to maintain the rail members as structurally simple as possible and provide a fitting at the vertical posts that provide a configuration for allowing a quick connection of the rails to the posts.
Hence, those skilled in the art have recognized the need for an improved means of interconnecting handrail components while keeping the handrail or railing design simple and with as few parts as possible. Preferably such a design would comprise a connector that could interconnect handrail components without requiring welding, bonding, or the use of threaded mechanical fasteners. Further, such a device should be reliable, allow easy and rapid installation, and should be relatively inexpensive to manufacture. A need has also been recognized for connectors and railing components that present a smooth outer surface when assembled that is both aesthetically pleasing and is decorative. The present invention fulfills these and other needs.
The present invention is directed to a connector for connecting to another component having a hollow section for receiving the connector. The connector in accordance with aspects of the invention includes a shank having at least one groove and an O-ring positioned in that groove.
In more detailed aspects, the railing connector in accordance with the invention comprises a shank, the shank having an outer diameter that is less than the inner diameter of the railing component to be mounted on the shank, a proximal end and a distal end for receiving the railing component over the shank, the shank having an annular groove, wherein the annular groove includes a bulkhead and a tapered portion with the bulkhead located closer to the proximal end and the tapered portion tapering outward toward the distal end, and an O-ring having an outer diameter that is larger than the outer diameter of the shank and being disposed in the annular groove, wherein when the railing component is received over the shank, the O-ring is moved against the bulkhead of the groove permitting the railing component to be moved proximally over the shank into a selected mounting position and when the railing component is moved in the distal direction, the O-ring moves up the taper of the groove and is wedged against the inner surface of the railing component thereby opposing further distal movement of the railing component.
In yet more detailed aspects, the annular groove has a seating area with the bulkhead being located proximal to the seating area and the taper of the groove being located distal to the seating area, the seating area having a size selected to receive the O-ring. In another aspect the seating area has a width approximately equal to the width of the O-ring and the seating area has a depth approximately equal to the inner diameter of the O-ring. Further, the annular groove has a seating area within which the O-ring rests, the seating area being located at a portion of maximum depth of the groove.
In yet other aspects, the seating area of the annular groove has a width within the range of about one half to about the full thickness of the O-ring. In more detailed aspects, the groove has a size selected to accommodate O-rings of different sizes so that railings of different inner diameters can be received by the shank and the O-ring of an appropriate size selected to wedge against the railing component. And further, the seating area of the groove is wide enough to accommodate different O-rings that have different outer diameters.
In other aspects of the invention, the outer diameter of the shank is small enough to accommodate railing components of different inner diameters and the seating area of the groove is wide enough to accommodate O-rings of different outer diameters so that the O-ring can be selected depending on the difference between the outer diameter of the shank and the inner diameter of the railing component. Also, the outer diameter of the shank is slightly smaller than the inner diameter of the railing component thus providing a small interference fit.
In another aspect in accordance with the invention, the connector further comprises a fitting to which the proximal end of the shank is disposed, the fitting comprises an abutment portion located at the proximal end of the shank, the abutment portion having an outer diameter approximately equal to the outer diameter of the railing component whereby when the railing is mounted to the connector, the abutment portion provides a smooth appearance between the railing component and the connector. Also, the abutment portion limits mounting movement of the railing component in the proximal direction. Yet further, the distal end of the shank includes a chamfer thereby making it easier to receive the railing component over the shank.
Another more detailed aspect of the invention includes a railing connector comprising a shank having a plurality of annular grooves wherein each annular groove includes a bulkhead and a tapered portion with the bulkhead located closer to the proximal end and the tapered portion tapering outward toward the distal end, further comprising a plurality of O-rings, each of which has an outer diameter that is larger than the outer diameter of the shank and each of which is disposed in a respective annular groove, wherein each annular groove has a seating area with the bulkhead being located proximal to the seating area and the taper of the groove being located distal to the seating area, the seating area having a size wide enough to accommodate different O-rings that have different outer diameters.
A further aspect includes locating the abutment portion of the fitting at the proximal end of the shank to limit mounting movement of the railing component in the proximal direction, the abutment portion having an outer diameter approximately equal to the outer diameter of the railing component whereby when the railing component is mounted to the connector, the abutment portion provides a smooth appearance between the railing component and the connector, wherein when the railing component is received over the shank, each O-ring is moved against the bulkhead of the respective groove permitting the railing component to be moved proximally over the shank into contact with the abutment portion, and when the railing component is moved in the distal direction, the O-rings move up the taper of the grooves and wedge themselves against the inner surface of the railing component thereby opposing further distal movement of the railing component.
Other features and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the features of the invention.